The present invention relates to a mechanical positioning jack which can be used in a simple and practical manner for an adjustment of the discontinuous positioning of the back of a seat, an adjustment in height of a sitting portion of a seat, an adjustment in height of a seat head-rest, the displacement of a slide for the longitudinal positioning of a seat, which seat is particularly a vehicle seat and more particularly an automobile vehicle seat.
Automobile vehicles, even less expensive automobile vehicles, are more and more provided with seat equipments for the driver and the front passenger, comprising adjusting elements so as to bring each seat in conformity with the morphology of the user of the seat, in order to avoid fatigue symptoms resulting from traveling in a vehicle.
But the longitudinal adjustment of the seat by using slides, the inclination adjustment of the back of the seat, the adjustment of the under-thigh cushion placed in front of the sitting portion of the seat, the adjustment of the lumbar cushion and finally the adjustment of the head-rest, all require rather costly mechanisms all having a the disadvantage of creating unpleasant sensations, since the respective play of these mechanisms resulting from their production cannot be entirely compensated.
This is the reason why one is led to study simple, inexpensive and play-free mechanisms able to perform the aforementioned functions.
The object of the present invention is therefore a mechanical positioning jack moving step by step, i.e., providing a discontinuous positioning without play, thereby providing maximum comfort to the driver and/or to the passenger.